The overall objective of this project remains as orginally proposed: the extension of mathematical models for prognosis and disease to "allow for the effect of treatment on the occurrence of signs and symptoms and on prognostic statements based on them." In particular, the theories developed have been directed toward analysis of real (and therefore incomplete) clinical data. Two general goals are set for the next year: first, extension of the model validation studies already under way to a considerably larger sample of relatively well-known populations; second, use of the programs on populations of diseased persons which are much less well-known and the data correspondingly softer. In pursuing the first goal, we will also work on development of computational procedures, which will lower computer costs considerably. For the second goal, Dr. Robert Rosati has made available data on 313 patients who entered Duke University Hospital with presumptive myocardial infarctions, and subsequent follow-up data; these data afford the opportunity to test the predictive accuracy of models of prognosis, and the relation between presenting symptoms, treatment, and outcome.